Manufacture of seamless tures



G. RABOLD, SR.

MANUFACTURE 0F SEAMLESS TUBES.

APPLICATION FILED MAR. 26,1921.

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G. RABOLD,-SR.

MANUFACTURE 0F SEAMLESS TUBES.

APPLICATION man MAR. 2s. 1921.

1,41 2, 1 96. Patented Apr. 11, 1922.

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UNITED STATES PATENT oFFlcE.-

'GEoRGEaABoLn siti, or McxEEsroRT,

TUBE conrANY, OEPITTSBURGH,

PENNSYLVANIA, ASSIGNOR T0 NATIONAL PENNSYLVANIA, A CORPORATION OF NEW MANUFACTURE or'` sEAMLEss Tunas. f

lApplication led March 26, 1921.

To all 107mm it may cm1/eem.'

Be 1t known that I, GEORGE RABoLD, Sr,

a citizen of the United States, and resident b of McKeesport, inthe county of Allegheny Th used to reduce the wall thickness of the tube.

Another and important object is the provision of a method whereby the end of a seamless tube may be internally upset for any desired length during the drawing operation.

The several successive steps of my process or method are illustrated in the accompanyin drawings, in which:-

igure 1 is a plan view of a square section of rolled plate or blank' from which the tube is to be formed.

Figure 2 is `a plan view of the plate or blank after it has been cut to circular form.

Figures 3 and 4 are sectional elevations of the plate or blank after it has passed through successive cupping operations.

Figures 5 to 9, inclusive, are sectional elevations of the blank after it has been drawn over successively smaller mandrels having reduced forward ends to forman internally upset portion.

Figure 10 is a sectional elevation of the completed tube sho-wing the closed end cut off.

In the operation of my improved method, a suitable rolled plate or blank 2 is cut cylindrical and then heated until it becomes f suliciently ductile to be cupped. The heated plate 2 is then forced through a suitable cupping die forming a cupped blank 3, as. shown in Figure 3. The cupped blank 3 is then reheated and forced through a smaller cupping die forming an elongated cylindrical cupped blank 4 of suicient size to be drawnfover a mandrel.

After the cylindrically shaped cupped blank 4 has been formed, itis reheated to a drawing temperature and placed on the Specification of Letters Patent.

. and diameter are Patented Apr. 11, 1922. Serial No. 455,844.

and the blank is drawn over the mandrel y .forclng it through a series of dies 7. 1s drawing operation will force the metal, at the orward or closed end 8 of the blank, mwardly around the reduced 4end 6 o-f the mandrel 5, forming an internally .upset portion 9, and since the metal of, the blank ylelds inwardly around the reduced portion of the mandrel the dies 7 will draw less metal from the walls of the blank over the mandrel 5 having a, reduced forward end 6,

upset portion than from the remalning portions, thus forming-a cylindrical blank having an internally upset portion 9 of greater wall thickness adjacent its closed end.

The blank 4 is, then reheated and drawn over successively smaller mandrels 5 having reduced inner ends 6, until the desired gage secured, the internally upset portion 9 being maintained throughout the successive steps.

After the blank is drawn to the desired gage and diameter the closed end 8 is cut oli'l by any suitable means, such as a lathe, and a finished open tube X is formed having the internally upset portion 9.

It will be understood that while I have shown two cupping steps and five drawing steps I do not wish to be limited tosuch number of steps since they may be varied according to the size and character of tube being formed. 1 I claim I 1. The method of making tubes having an internally upset end, which consists in formmg a cupped blank, reducing the blank to gage and diameter in subsequent drawing steps, and upsetting the blank internally adjacent its cupped end in one of the drawing steps and maintaining said upset end duringthe subsequent drawing steps.

2. The inethod of making tubes having an internally upset end, which consists in orming a cupped blank, drawing said blank through suitable dies over a mandrel to reduce its forming a cupped blank, drawing saidgage and diameter and to in# Aternallynpset said blank adjacent its closed blank through suitable dies over a mandrel to reduce its gage and diameter and to internally upset said blank adjacent its closed end, reducing said blank to finished gage and diameter by a plurality of subsequentl drawing operations, maintaining said upset end during the subsequent drawing operations, and cutting oli' the closed end of the blank to Jform an o )en tube.

4. 'lhe method o making tubes having an internally upset end. which consists in forming a cup ed blank, drawing said blank through suitable dies over a mandrel of reduced diameter toward its inner end to reduce the gage and diameter of and internally upset said blank, reducing said blank to finished gage and diameter by a pluralit of subsequent drawing operations, in which said blank is drawn through successively smaller dies and over successively smaller mandrels, and maintaining said internally upset portion of the blank during said subsequent drawing operations.

5. The method of making tubes having an internally upset end, which consists in forming a cupped blank, drawing said blank through suitable dies over a mandrel having its inner end reduced forming a shoulder thereby' reducing the gage and diameter of said blank and forming an internall" upset portion of greater Wall thickness ac jacent its closed end, reducing `said blank to finished gage and diameter by a plurality of subsequent drawing operations, in whic 1 said blank is drawn over successively smaller mandrels having correspondingly reduced inner ends, thereby maintaining said internally upset portion during said subsequent drawing operations, and removing theI GEORGE RABOLD, Sn. 

